Hard to tell... I think most programs will compile (and - even better - work), but quite a few are masked or don't have an AMD64 keyword at all.
The stuff that won't compile usually relies on x86 assembler, like zsnes and such.

I've had a couple of hard-locks whielst running Kaboodle...nothing I can prove is Kaboodle's fault though. I'm going to do some more testing on it. Once I'm done being lazy I'll merge a real video player Anywho, I agree with the comment made about most things working, just requires a little patience with editing some ebuilds.

Outside of the beaten track (ie X, the major window managers, desktop environments, standard utilities, common applications), linux on amd64 is still something of a get-your-hands-dirty propositon. Most things can be made to work, however. A large number of packages are already written with portable code, and are just waiting to be marked compatible....take a look at bugs.gentoo.org and see the number of "please add ~amd64 to foox.y" reports. You'll probably learn to love running a ~amd64 system, though, if you want access to a lot of software.

Other programs require a bit more doing to get working....bugs, incompatibilities, etc. But the forums provide great help, and the developers are very active on the bugzilla site. I've quite literally seen packages go from "won't work" to "here's a workaround" to "here's a fix" within a few days. Of course, that's little consolation if you're in a situation where you need things working *right now*, but on the other hand it really feels good to know that you were instrumental in getting something working on the platform.

The 32 bit compatibility is something I've not played with all that much. To my understanding, you should be able to get just about anything working on a 64-bit system, under ia32 architecture emulation. But this lacks much (if any) support in portage. Different people have had success either compiling the old-fashioned way (sans portage, tweaking the makefiles by hand...) or adapting other distributions precompiled packages.

Nonetheless, the whole system is stable enough to get real work done, but it's fun and geeky to play around with when you feel like it....

the "emulation" really is just a set of compatibility libraries...it really doesn't cause your system to do anything different other than allow 32-bit binaries to have access to 32-bit libs. There are also some apps that REQUIRE the 32-bit environment as they do not compile under 64-bit yet. OpenOffice is one such application.

the "emulation" really is just a set of compatibility libraries...it really doesn't cause your system to do anything different other than allow 32-bit binaries to have access to 32-bit libs. There are also some apps that REQUIRE the 32-bit environment as they do not compile under 64-bit yet. OpenOffice is one such application.

So emulating 32bit mode is a neccesity if i want to run openoffice, right?

Yes, you'll need the 32bit emul-libs for OpenOffice, and for MPlayer or Xine if you want to use win32 codecs (You need a 32bit MPlayer for that).
But 32bit apps run at native speed, side-by-side with 64bit apps without any problems.